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Venus passes in front of the sun in rare spectacle

Stargazers around the world were united Tuesday evening as they looked skyward to watch the planet Venus as it appeared to race across the face of the sun.

The next transit of Venus won't be for another 105 years, making this a once-in-a-lifetime event, said Jesse Rogerson, a researcher and programmer in astronomy and space sciences at the Ontario Science Centre.

There have only been seven transits of Venus since the invention of the telescope in 1610.

Venus makes its visible trek across the sun twice a century, in crossings eight years apart.

"There was a crossing in 2004, and it was spectacular. It was the first time that Venus has made this crossing in 120 years," Rogerson told CTVNews.

The pairs of rare events are typically either 105.5 years or 121.5 years apart, he said.

That means the next pair will not happen until 2117 and 2125.

Skywatchers, who needed to use protective glasses to avoid damaging their eyes, could see Venus appear as a black blemish moving across the sun.

In Toronto, thousands of amateur astronomers gathered at Varsity Stadium, near the University of Toronto, where they were handed disposable glasses, which would protect their eyes from the sun.

They began watching the event at 6:04 p.m. ET. The event lasted two hours, before the sun set.

Scientists are using the transit of Venus to dig deeper into the mysteries of the universe.

NASA's Hubble Space Telescope studied the event by pointing in the direction of the moon, not the sun.

"Pointing it at the sun would be too bright and damaging to the Hubble," said Rogerson.

From this vantage point, scientists hoped to learn new information about Venus' atmosphere.

"As Venus crosses the sun, its atmosphere will leave telltale marks on this reflected light. These details can be used to estimate such physical characteristics as the size of the planet, how hot or cold it is and other qualities," said Rogerson.

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Photos

Venus travels between the sun and the earth, in what is known as a Venus transit, in this image taken through a telescope, inverting the image, at Central Lakes College in Brainerd, Minn. on Tuesday June 5, 2012. (AP / Brainerd Dispatch, Kelly Humphrey)